Okay so this seems to be a tough balance to create.

This game would be a 1 v 1 pvp with 2 classes: mage and warrior

The only way I can ensure the mage won't win all the time against a warrior is

1) if the mage can fire spells while being immobile.

2) comparison to the mage, the warrior is slightly quicker.

3) comparison to the warrior, the mage attack power is slightly stronger

4) comparison to the mage, the warrior has slightly more armor and hp.

None of the actual game has been developed but I thought I draft up a small design document like this before development starts.

Any thoughts?

Mages--and spells--don't have to be extremely powerful, and warriors don't have to be ponderous and limited to simple attacks.

For example, compare the warrior and the mage in Hexen: if I recall correctly, the former was very fast and had powerful attacks, but leaned towards melee weapons, while the latter was slow and had weaker attacks, but had the advantage that all of his weapons were ranged.

There are other approaches: instead of nukes, give mages lots of utility spells and only a few attacks; give warriors an ability that deflects incoming attacks if used properly (a spell-reflecting shield, perhaps); give warriors abilities that allow them to close on unwary mages (a "dash" ability, for example); and so on.

None of the actual game has been developed but I thought I draft up a small design document like this before development starts.

If I may make a suggestion, try prototyping it instead: experiment. You needn't worry about networking (unless you have that in place already, of course)--your prototype might work if played in split-screen by two players at a single keyboard.

As Thaumaturge said, prototype (doing balance on paper almost never makes sense). Overall people worry WAY too much about balance. In most cases it's easy to do (if you have time), just halve/double magic damage value until you hit the spot. And then play test, players will tell you which is overpowered and again (usually) you can rebalance it by changing one or two numbers.

try prototyping it instead

+1

Also, there's more to theoretical balancing than how you've presented it.

I actually make a living lining up numbers to make them balance in the context of a game and it is never that straightforward.

The more subtle the balance, the better the game.

I'd start by designing one class which has a broad set of mixed warrior and mage abilities (like a naruto-style ninja) and let the playtesters pick which few abilities they want to invest in from the broader set. Then balance the individual abilities against each other, with one of the balancing goals being that an all-mage or all-warrior set should be viable builds.

If I may make a suggestion, try prototyping it instead: experiment. You needn't worry about networking (unless you have that in place already, of course)--your prototype might work if played in split-screen by two players at a single keyboard.

Okay, time to prototype! I have a lot of infrastructure code from my other game projects to build off of. The game will mostly likely not use any "networking" concepts as I never worked with sockets and packets or any networking libraries. Instead it will just be a game that can be played by two people provided 2 usb keyboards are connected.

There are other approaches: instead of nukes, give mages lots of utility spells and only a few attacks; give warriors an ability that deflects incoming attacks if used properly (a spell-reflecting shield, perhaps); give warriors abilities that allow them to close on unwary mages (a "dash" ability, for example); and so on.

Whoa! Good ideas! I never thought of that. I see what you mean. I see games do this too but I overlooked this important idea. Thanks for the reminder!

I remember the "Litany of curses" from Planescape Torment. A (close combat) character could make a mage furious with insults so badly, the mage couldn't help but attack physically (which naturally was weaker than spells). Most RPGs also have some kind of silence spell to mute mages. A look at some AD&D skills should give you some ideas.

A idea what I just had is again some special equipment, e.g. a sword which can absorb fireballs - and make it a fiery sword for the next blow.

An other approach: how would a balanced combat scene between a warrior and a mage would look like (eg in a movie) ?

If you look at a balanced (cinematic) battle between two warriors, it would look like attack->defend->counter->...->attack->failed defense->hit->recover

If you would transfer the same to warrior vs mage scenario, what would be a successful attack of a warrior

1. close distance (a warrior is more deadly if he is close to the mage)

2. ranged attack (throwing dagger, arrow)

The mage/warrior combat situatoin lives from the deadly strike scenario, where a single,simple attack will most likely slay the mage.

How would the mage defend vs these attack

1. close distance: wind blow (push back), root (hold in place), teleport (escape), poison cloud(blockade)

2. ranged attack (magic shields, throw an object to block incoming projectiles, blink)

How would the mage attack ?

1. magic projectile (much like warrior ranged attack)

2. movement control (do not let the warrior close in)

3. avoid death nukes (snap your fingers and warrior is dead)

How would the warrior defend ?

1. blocking (shield, dodge,seek cover,deflect/parry)

2. interrupting/distraction by using ranged attack

It is important to note, that in such a scenario the warrior only uses a sub-set of his skills, but the mage too (creating a bottle of tasty water during combat isn't that useful), because a single close combat attack would most likly kill the mage.

Just a thought.